• Review Requirements for replacing a DE6400 or DE6600 DIMM.• Make sure that no volumes are in use or that you have a multipath driver installed on all hostsusing these volumes.• Make sure you have the following:◦ A replacement DIMM.◦ An ESD wristband, or you have taken other antistatic precautions.◦ A flat, static free work area.◦ Labels to identify each cable that is connected to the controller canister.◦ A management station with a browser that can access ThinkSystem System Manager forthe controller. (To open the System Manager interface, point the browser to the controller’sdomain name or IP address.)4.2.1. Step 1: Determine if you need to replace a DIMMVerify the cache size of your controller before replacing the DIMMS.Steps1. Access the Storage Array profile for the controller. From ThinkSystem System Manager, go toSupport › Support Center. From the Support Resources page, select Storage Array Profile.2. Scroll down or use the Search field to locate the Data Cache Module information.3. If one of the following is present, note the DIMM’s location and continue with remainingprocedures in this section to replace the DIMMs on your controller:◦ A failed DIMM, or a DIMM reporting Data Cache Module as not optimal.◦ A DIMM with a mismatched Data Cache Module capacity.4.2.2. Step 2: Place controller offlinePlace the controller offline so you can safely remove and replace the DIMMs.Steps1. From ThinkSystem System Manager, review the details in the Recovery Guru to confirm thatthere is an issue with a mismatched memory and to ensure no other items must be addressedfirst.2. From the Details area of the Recovery Guru, determine which DIMM to replace.3. Back up the storage array’s configuration database using ThinkSystem System Manager.If a problem occurs when you remove a controller, you can use the saved file to restore yourconfiguration. The system will save the current state of the RAID configuration database, whichincludes all data for volume groups and disk pools on the controller.◦ From System Manager:33